1 // Copyright (c) 2010, Atmel Corporation.
2 // All rights reserved.
3 //
4 // Redistribution and use in source and binary forms, with or without
5 // modification, are permitted provided that the following conditions are met:
6 // * Redistributions of source code must retain the above copyright
7 // notice, this list of conditions and the following disclaimer.
8 // * Redistributions in binary form must reproduce the above copyright
9 // notice, this list of conditions and the following disclaimer in the
10 // documentation and/or other materials provided with the distribution.
11 // * Neither the name of Atmel nor the
12 // names of its contributors may be used to endorse or promote products
13 // derived from this software without specific prior written permission.
14 //
15 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
16 // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
19 // DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
20 // (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
21 // LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
22 // ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
24 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25
26 #include <stdint.h>
27 #include "SHA_TimeUtils.h"
28
29
30 // The values below are valid for an AVR 8-bit processor running at 16 MHz.
31 // Code is compiled with -O1.
32
33 //!< Offsets time needed to prepare microseconds loop.
34 #define SHA_TIME_OFFSET_US (7)
35
36 //!< Fill a while loop with these CPU instructions to achieve 1 us per iteration.
37 #define SHA_TIME_LOOP_FILLER asm volatile ("nop\n\tnop\n\tnop\n\tnop\n\tnop\n\tnop\n\tnop")
38
39
40 extern void SA_Delay(uint32_t delay);
41
42
43
44
45
46
47 /** \brief Delays for a certain amount of time.
48 *
49 * \param[in] delay Delay for this number of microseconds (us).
50 */
SHAP_Delay(uint32_t delay)51 void SHAP_Delay(uint32_t delay) {
52 if (delay <= SHA_TIME_OFFSET_US)
53 // We spent already this much time entering this function.
54 // With other words: A value <= SHA_TIME_OFFSET_US will not produce the desired delay.
55 return;
56
57 delay -= SHA_TIME_OFFSET_US;
58
59
60 SA_Delay(delay);
61
62 return;
63 }
64
65
loop_delay(int8_t multp)66 void loop_delay(int8_t multp) {
67 int i, base = 2000000 *multp;
68 for(i=0;i<base;i++) {
69 double value = 10.0; //((i * 33.3) - 12.1) / 10.0;
70 value += 1.0;
71 }
72 }
73